Installing alsa

The kernels I used so far didn't work with this soundcard (hda-nvidia), so I had to install the stand-alone driver.
Support for kernel 2.6.24 was added on alsa 1.6, but, if you look at portage tree right now (i mean, by the time i'm writing this), you´ll notice that only version 1.5 is available. So the only way to have a working version is using the repository version (9999).

To do this, unmask this version on /etc/portage/package.unmask by adding:
=media-sound/alsa-driver-9999
=media-sound/alsa-headers-9999

And then add this to /etc/portage/package.keywords:
media-libs/alsa-lib
media-sound/alsa-driver **
media-sound/alsa-headers **
media-sound/alsa-utils

Doing this will make you able download the repository versions for alsa driver and headers, and the latest version of alsa-lib and alsa-utils. You'd also like to configure your /etc/make.conf to match the soundcard model by adding this:
ALSA_CARDS="hda-intel"

Just emerge'em'all now and you'll have your soundcard up and running
'rc-update add alsasound boot' will help storing your volume settings